The major goal of this proposal is to create microfluidic cell separation systems to isolate or enrich key cell types for tissue engineering and regenerative medicine. In conventional tissue engineering, functional cell types must be enriched prior to seeding onto scaffolds. In cell-based approaches to tissue repair and regeneration, stem and progenitor cells resident in different tissue types must be isolated and characterized prior to their use. The design and fabrication of microfluidic cell separation systems for these applications is motivated by the following observations. First, in functional cell enrichment, microfluidic techniques are more systematic compared to state of the art methods such as pre-plating and using cell strainers. Second, microfluidic systems can handle small (microliter-order) sample volumes, enabling effective cell separation from small quantities of donor tissue. These systems can be incorporated with in-vitro cell culture equipment and furthermore, they are low-cost and easily operated on-site in clinical settings. Third, recent work in the PI's laboratory has demonstrated the ability of microfluidic devices to separate cell subpopulations based on size and affinity. This proposal will focus on the creation of microfluidic cell separation technologies for tissue engineering applications in four areas: cardiac tissue, skin, gastrointestinal tissue, and vascular tissue. The proposed work will be carried out in collaboration with experts in tissue engineering: Drs. Milica Radisic (cardiac), Rebecca Carrier (intestinal), Virna Sales &John Mayer (vascular), and Yaakov Nahmias &Martin Yarmush (skin/burns). During the 3-year project period, the following aims will be pursued along independent tracks: (1) design and fabricate size- and adhesion-based microfluidic separation devices to separate cell populations in cardiac and intestinal tissue;(2) design an adhesion-based microfluidic separation approach to isolate endothelial progenitor cells and skin stem cells by positive selection for regenerative applications;and (3) design an adhesion-based microfluidic separation approach to isolate cardiac progenitor cells and intestinal stem cells by negative selection. PUBLIC HEALTH RELEVANCE: The ability to grow sections of certain tissue types from a small sample of donor tissue, tissue engineering has grown tremendously in recent years. Recent work has also demonstrated how stem and progenitor cells resident in adult tissue can play a role in repairing tissue. A key component of either of these approaches is the requirement to isolate or harvest certain cell types prior to utilizing them for repair and regenerative applications and this proposal aims to create novel tools for this purpose.